1. Field of the Invention
Embodiments of the present invention relate to a sound field effect adding apparatus and process which is used with an electronic musical instrument such as, for example, an electronic organ that is equipped with a speaker system that can reproduce the low frequencies, where reverberation and the like are added to the musical tone signal of the electronic organ to produce a sound field effect. Further embodiments of the invention relate to an audio system in which such a sound field effect adding apparatus is employed.
2. Description of Related Art
A sound field effect adding apparatus is a device with which, by the addition of the indirect sounds to so called direct sounds, produces a sound field that approximates the presence of a performance venue. The direct sound may be produced by a musical instrument, such as an electronic organ. The indirect sound may include sound reflected by, for example, the walls and ceiling of the performance venue. A sound field effect adding apparatus may produce a sound field that accounts for such things as the arrangements of each of the musical instruments in the performance venue and the characteristics of the audio space of the performance.
By using, for example, three-dimensional stereo image orientation technology and also adding directional information for three-dimensional space, the production of a sound field that has more presence is realized. Normally, in the creation of a reproduced sound field that has presence, a multichannel speaker system (in general, a speaker system on the left and right and/or the rear and the front) is included in or connected to the instrument or system from which the musical tone signals are emitted.
Some electronic musical instruments such as electronic organs can produce musical tone signals in the low frequency range (for example, the audio band of around 100 Hz or less). Typically, such instruments, when used in a performance venue, are set up with or connected to a speaker system that includes speakers capable of producing the entire audio band, including low frequency tones and, by this means, it is possible to have good quality audio reproduction of the musical tones.
Because of this, in order to create a satisfactory reproduced sound field with a sound field effect adding apparatus, the speaker system for the sound field effect adding apparatus must be capable of reproducing the relevant low frequencies. Therefore, it is desirable to provide a speaker system that can reproduce the low frequencies for each channel in the same manner as the low frequencies can be reproduced with the above-mentioned multichannel speaker system. Alternatively, it may be necessary to provide a dedicated speaker system (woofers and the like) for the reproduction of the low frequencies that is separate from the above-mentioned multichannel speaker system. However, a speaker system for the reproduction of the relevant low frequencies can be relatively expensive.
In consideration of the above noted problems, one aspect of preferred embodiments of the present invention is to make it possible to create a satisfactory reproduced sound field that has had a sound field effect with a low frequency component added, where the speaker system that has been installed in the electronic musical instrument is used as the speaker system for the production of the sound field. In this manner, a dedicated speaker system that can reproduce the low frequency tones is not necessary and, preferably, is not employed as the speaker system for the production of the sound field.
A sound field effect adding apparatus according to an embodiment of the present invention is equipped with an input terminal with which a musical tone of an audio band that includes a low frequency is input. The apparatus further includes a first generation means in which a sound field added musical tone signal is generated in order to produce a sound field effect that is based on a musical tone signal that has been input from the input terminal. The apparatus also includes a first output terminal for the output of the sound field added musical tone signal that has been generated in the first generation means to a speaker system used for sound field reproduction. The apparatus is provided with a second generation means in which a low frequency component of the sound field added musical tone signal that contributes to the production of a low frequency sound field effect is generated, where the low frequency component is different from the sound field added musical tone signal that is output by the first output terminal. The apparatus includes a second output terminal with which the low frequency component that has been generated in the second generation means is output to an external device.
A sound field effect adding apparatus, according to embodiments of the invention, may be provided with an output setting means in which the sound field added musical tone signal that has been output to a front speaker system (from among the speaker systems used for the above-mentioned sound field generation) is added to the low frequency component that has been generated in said second generation means and is output from said second output terminal to an external device.
Further embodiments relate to an audio system for use with an electronic musical instrument. In such embodiments, the audio system is configured using the above-mentioned sound field effect adding apparatus and, in preferred embodiments, also includes an electronic musical instrument that is provided with or connected to a speaker system for audio reproduction of audio tones across the audio band, including the low frequency tones. The audio system is configured so that the musical tone signal that is generated by the electronic musical instrument is supplied to an input terminal of the sound field effect adding apparatus. The sound field added musical tone signal that is output from the first output terminal of the sound field effect adding apparatus is supplied to said speaker system used for the production of the sound field, while the output signal that, is output from the second output terminal is supplied to said electronic musical instrument and emitted by the speaker system with which said electronic musical instrument is equipped.
By this means, since the portion of the sound field effect that is produced due to the contribution of the low frequency component is produced by the speaker system of the electronic musical instrument, there is no need to have the speaker system used for the production of the sound field provided with a low frequency reproduction capabilities. In this manner, the low frequency component is emitted only by the electronic musical instrument. However, since, in general, listeners are not very cognizant of the stereo position of low frequency tones, it is possible to fully provide the listeners with a good sound field effect.
Typically, the electronic musical instrument is arranged on a stage in front of the listeners and a speaker system used to produce the sound field is arranged behind the listeners as the rear speaker system. However, an additional front speaker system may also be provided. In the case of an audio system that is not equipped with a front speaker system, the sound field added musical tone signal that would otherwise be supplied to the front speaker system has the above-mentioned low frequency component added by the output setting means and is output to the electronic musical instrument. Thus, the speaker system of the electronic musical instrument can serve double duty as the front speaker system for the sound field production.